| Project/Area Number |
16590001
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Chemical pharmacy
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| Research Institution | Kumamoto University |
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Principal Investigator |
NAKAJIMA Makoto Kumamoto University, Faculty of Medical and pharmaceutical Sciences, Professor, 大学院・医学薬学研究部, 教授 (50207792)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2005: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2004: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Organocatalyst / Asymmetric synthesis / Phosphine oxide / Allylation / Aldol reaction / Epoxide / Silyl enol ether / Silicate / 不斉触媒 / エナンチオ選択性 / ジアステレオ選択性 / 不斉アルドール反応 / トリアルコキシシリルエノールエーテル / リチウムビナフトラート / 不斉アリル化反応 |
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| Research Abstract |
Organocatalysis has been one of the current hot topics in the field of synthetic chemistry because of its environmentally benign nature. Recently, asymmetric organocatalyses utilizing neutral Lewis bases attracted much attention because it led to the emergence of new types of chiral ligands based on functional oxide compounds. Phosphine oxide has high polarity and relatively low Bronsted basicity, whose reactivity is expected to be similar to those of such Lewis bases. Moreover, various types of chiral phosphine oxides can be easily obtained by the simple oxidation of commercially available chiral phosphines. However, the examples of the application of chiral phosphine oxides to asymmetric organocatalyses are still limited. We investigated the catalytic activity of BINAPO, which is easily prepared from the most common chiral phosphine ligand BINAP. We found that BINAPO was an effective catalyst for the enantioselective allylation of aldehyde with allyltrichlorosilane and the enantiosel
… More
ective aldol reaction of trichlorosilyl enol, wherein the allylated adducts or aldol adducts were obtained in high diastereo- and enantioselectivities (up tp 96% ee). BINAPO was found to be effective in the enantioselective ring opening of meso-epoxides with tetrachlorosilane in the presence of diisopropylethylamine, affording the corresponding chlorohydrins in high enantioselectivities of up to 90% ee. An aldol reaction of trimethoxysilyl enol ether catalyzed by lithium binaphthoxide was also developed. The aldol reaction of trimethoxysilyl enol ether derived from cyclohexanone under anhydrous conditions predominantly afforded the anti-aldol adduct with moderate enantioselectivity, whereas the reaction under hydrous conditions predominantly resulted in the syn-adduct and the enantioselectivity of the syn-adduct was considerably improved. The best enantioselectivity was obtained in the reaction of trimethoxysilyl enol ether derived from 1-indanone with cyclohexanecarboxaldehyde (97% ee (syn)). This is the first example of an aldol reaction of trimethoxysilyl enol ether catalyzed by a chiral base. Less
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